Thermal and magnetic means of indicating temperature and electric failure



1953 J. N. M lNNES ETAL 2,563,859

THERMAL AND MAGNETIC MEANS OF INDICATING TEMPERATURE AND ELECTRIC FAILURE Filed Feb. 12, 1951 Patented Dec. 22, 1953 THERMAL AND MAGNETIC S OF INDI- f CATING TEMPERATURE AND ELECTRIC v FAILURE Machines; wfield's, and Paul H. Gerard, 1

Newmarket, N. H. I

a Application February 12, 1951, Serial No. 210,565

This invention relates generally to the class of electric signaling and is directed particularly to a system for use in connection with building heat-r ing and temperature indicating apparatus.-

The object of the present invention is to provide a means of indicating temperature change and electric failure in connection with heating apparatus, such as oil burners, to give notice of the failure of electric current controlling the operation of such apparatus and/or the dropping of the building temperaturebelow a desired level.

7 Another object of the invention is to provide a signal system of the character stated with means therein for energizing a signal in the event of overheating of the heating apparatus.

- It isalso an object of the invention to provide means for accomplishing the stated results, embodying two signals one of which is active when the heating equipment is operating properl and the temperature is correct,'the other signal come ing into operation and thefirst becominginactive when the reverse conditions prevail.

Th present application is acontinuation-inpart of our pending application Serial No; 145,324, filed February 21, 1950.

The invention will be best understood from a consideration of the following detailed description taken in connection with the accompanying drawing wherein the single figure is a diagrammatic layout of the electrical system constituting the invention. V

Referring now more particularly" to the drawing the reference character lil generally designates a portion of an outside wall of a building.

Exteriorly of the building is located, upon the wall or in any suitable location, a suitable receptacle [2, in which are mounted, to be clearly seen, the two signal lights 14 and [6, which are preferably, respectively red and green.

Within the building, as at I8, is a two circuit controlling electric relay, generally designated 20. This relay comprises the two circuit con- 2 Claims. (01. 340-227) .nected by the conductor 39 with one side tion or further description of the same is necessary. 'This conductor is connected to one side of a thermostatic-switch which is within the building and closed at room temperature, theother side of which is connected to one side of the coil 26 by conductor 3|. ---'Ihe other side of the coil is connected by conductor 32 to the return conductor 33 of the low voltage supply source, which conductor is also connected to one side of' the green signal bulb l6. i 1

The armature 24 of the relayis electrically connected by conductor 34 with the current supply line 28, and when the coil 26 is energized the armature 24 will be shifted to close the contacts 35 to complete the circuit for the bulb I6 through the conductor 36. u I The numeral 38 designates a source of electric potential, one sid of which iselectrically conof the red signa1light l V The other side of the light [41s connected by conductor .with one ofthe two contacts 4|,

' the other one of Which-is carried bythe armature :The numeral 42 designates a normally closed thermal switch; comprising a bimetallic strip 43. carrying one of two contacts 44, the other one of which is connected by the conductor 45, with y the other side of the current source 38;

trolling armatures 22 and 24 both of which are under the control of an electromagnet coil 26.

The numeral 28 designates a conductor forming one side of an electric circuit drawing ourrent from the low voltage side of the heating equipment. The most convenient source of such low voltage is the stack control of the burner. Such stack control has such low voltage current available as long as the burner is functioning properly and the power supply is not impaired. Since such stack control is standard equipment used on all automatically controlled and fired heating systems, it is not thought that illustra- The bimetallic strip 43 is electrically connected by :the conductor 45 with the red signal circuit closing armature 22. v a

In the operation of the system, in the event of power failure, overheating, failure to ignite properly, very poor combustion, or any other fault that might cause the stack control to cut-out,

the low voltage current supplied by the circuit conductors 28--32,'is shut on. When the supply of low voltage current is shut off, light I6 is ex-v tinguished and magnet 23 is deenergized allowing points M to close thus completing the circuit of lines 46 and 39, causing light 14 to become energized and giving warning of the condition that exists. This action would accomplish all that is desired except for the fact that in the majority of heating installations the radiation is inadequate to take care of the output of the furnace. This brings about an overheating condition which is prevented from becoming dangerous by a limit control, not illustrated, which is'a part of the standard oil burner circuit. Whensuch overheating condition occurs the limit control shutsoff the burner by cutting off the power supply to the stack control, thus shutting off the lower i voltage supply. When this latter action occurs .the reaction, as far as the present signal device tion, thermal element 42 is installed on or near,

a heat convector so that, in the event of overheating, the bimetallic elementi43 wi-llnpen contacts 44 and will prevent a complete circuit from becoming established in the circuit 4639, so that light l4 cannot give a false inrthe event of overheating, green light l6 will ge out... but red light [4 will not light ,due ,to thaaction of Thus if circuit is thermal element 42.

rendered incomplete by either, or both, thezaction of thermal element 42 or the armature 20, the lights will not he*energised;

. It thealow voltage supply from thestack-control err-circuit. 28-43 is shut off due to the-stack control'fcutting out, as a result-of a faulty burner, or is shut-off due to power line failure, the con--v vector which unit 42 is onor near, will be relativelyrcool, and thus the bimetallicelement 43=;wi-ll. allow contacts Mtoremain closed, thus action-oi armature .10 will complete the circuit to energize light 14, which is proper.

The stack control, thereinbefore referred. to is a standard unit as previously stated which is commamy n all automatically controll i of these staclr' andfired heating systems. controls embpdy a. 24 voltsuppl-y which isderived from a transformer with said stack controls are normally equipped. In the: present invention. the stack. control serves only asa source 0f current. Supply to actuate the present invention. The invention itself doesp not any wayail'iect the operation *oi the staclccontrol.

The-invention has. been thus-far described connection with its use with heating equipment employing a stack control unit but it is also de1-. for usewith automatic gas-fired heaters andwhenzso; employed the circuit wires- -28"-.-;3il would-be connected to: the-solenoid valvencircuit inasmuch as most-gas firedheating' units-arendt equipped with stackscontrols.

Weclaimr 1. Means for indicating current failure in a rincipal electric circuit, comprising signal element connected in series in said circuit, a relay including a magnet coil and two parallel conductors movable as a unit between a first position in which the unit is held by the energized coil and a second position, one of said conductors being in series connection in said circuit when said unit is :in. said first position, said magnet coil being connected in the circuit in bridge across the signal element and the conductors, a second cirunit, an electric signal element in series in the .secondcircuit, the other one of said conductors being arranged for connection i series in the second circuit whensaid unit assumes its second position upon deenergization of said coil, 2. source of electric potentialfor the second circuit independent from the current source for the first -.circuit;and;a normallyclosed thermal switch in said second circuit designed to open in a temperattire-above a pre-selected normal.

2. Means for indicating current failure in a principal electric circuit, comprising an electric signal element connected in series said circuit, a relay including a magnet coil-and two parallel conductors movable as a unit between a. first position in which theunit is heldby the energized coil and a second position, one ofvsazidconductors beizng in series connectionin said circuit whenzsaid unit is insaidfirstposition, said magnet coil being :connected in the circuitin bridge across the signal elementaand the conductors, a second circuit, an electric-signal element in series in the second circuit-,the other one of said'condu'ctors being arrangedxfor connectionin. series the second circuit when said unit assumes its second position upon deenergi'zati'on-of SBid'xCOll, a source of electric potentialsfor the second circuit independent from the current source .for'the:

, first circuit, a thermostatic switch connected.

series with. saidmgnet :coil: in'sbridge across the signal element and the conductors, and a; mor mally closed thermal switch: in said second. circuit designed to open a temperature above a rare-selected normal.

' JOHN'N. MACINNES'.

PAUL H. GERARD.

ReferenceswCited the file of this patent unrrnn s'rA'rE's PATENTS Gordon: c c June 13'," 1950 

